Mask



FIG. 1 is a perspective view of a mask shown on a head;

FIG. 2 is a perspective view of the mask of FIG. 1 shown without a head;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is front view thereof;

FIG. 6 is a rear view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a top view thereof.

The broken lines shown in the figures depict portions of the mask that form no part of the claimed design. The broken lines showing a head in FIG. 1 are for illustrative purposes only and form no part of the claimed design. 

CLAIM The ornamental design for a mask, as shown and described. 